Optical transceivers send and receive data in an optical form over an optical link, such as a fiber-optic link. An optical transmitter can include laser driver circuitry to drive a laser or diode, such as a light-emitting diode (LED), to create optical pulses on the fiber-optic link from received electronic signals. An optical receiver can include a photosensitive diode to receive optical signals, which are then converted into electronic signals. Thus, an optical transceiver converts (i) optical signals into analog and/or digital electronic signals, and (ii) electronic signals into optical signals.
In order to determine if the optical transceiver is functioning correctly, various operational parameters are monitored. Flags are then generated to demonstrate the status of the operational parameters. In conventional approaches, the flags indicate whether a parameter is greater than or less than a predetermined threshold value. For example, a flag may indicate that a monitored temperature value is slightly greater than a predetermined temperature value (e.g., a high temperature warning threshold). In some embodiments, a flag may indicate that a monitored temperature value is significantly greater than a predetermined temperature value (e.g., a high temperature alarm threshold). Thus, conventional transceivers monitor certain parameters to generate one or more flags that indicate when a parameter value is higher or lower than a predetermined operating value.
However, a drawback of this approach is that multiple flags may be indicated at the same time, or in rapid succession, resulting in conflicting or ambiguous indications. For example, a flag-based system may generate a warning flag and, subsequently, an alarm flag as the value of a parameter rises past the warning threshold and then past the alarm. A user checking the system may see two flags: a warning flag and an alarm flag. However, the user does not know whether the parameter value is still in an “alarm” state, or whether the value of the parameter has since lowered or decreased, for example, to the “warning” level, but has not updated the alarm flag. A user may have to assume that the parameter value is still at an “alarm” level, which would necessitate drastic and possibly unnecessary action, or request further data from the device, reducing the efficiency of operation. As a result, this system does not provide adequate information to a user.
Furthermore, in conventional single-bit flag systems, a register may be a predetermined number of bits wide, and each bit may correspond to a flag. An exemplary mapping of flag values to states is shown in Table 1.
TABLE 1Binary Flag ValuesState0000Normal0001Below Warning Low0011Below Alarm Low0100Above Warning High1100Above Alarm High
However, the above configuration leaves many combinations of flag values unused because they provide little or no usefulness to the user (e.g., binary code 1111, representing a simultaneous indication of “Alarm Low” and “Alarm High”). Thus, in a conventional method or device, there may be a relatively large amount of memory overhead and/or resources wasted in storing, accessing, and processing flag data relating to one or more parameters of the device.